Suspension device



Sept. 15, 1970 A. GANT 3,528,679

SUSPENSION DEVICE Filed March 5 1968 2 Sheets-Sheet l Amen/e54 a/wr I NVENTOR.

477'0R/VEVS Sept. 15, 1970 L. A. GANT 3,523,679

SUSPENSION DEVICE Filed March 5 1968 2 Sheets-Sheet :3

(AW/PWC! 4. 6A/v7' INVENTOR.

ATTOP/VEVS US. Cl. 280-124 1 Claim ABSTRACT OF THE DISCLOSURE Asuspension device to improve vehicle mobility comprising means disposedabove a vehicle tire to limit and cushion its extreme verticaldisplacement by contact there with. Interruption of the verticalmovement compresses' the tire thereby cushioning and dampening itspassage.

The invention described herein may be manufactured, used and licensed byor for the Government for governmental purposes without payment to me ofany royalties thereon.

This invention relates to high mobility wheeled vehicles. Moreparticularly, this invention relates to a suspension device forimproving vehicle mobility.

In a normal suspension system, there may exist many different deviceswhich improve riding stability such as a coil spring, a leaf spring,and/or the tires on which the vehicle is transported. When vehiclesutilizing these prior are devices encounter irregularities in thetraversed surface, however, they tend to bounce or oscillate in avertical direction. To eliminate this problem, shock-absorbing deviceswere mounted on the vehicle in order to absorb the oscillatory movementof the vehicle. Although this had many advantages, it also had manydisadvantages and did not completely eliminate all of the bounceintroduced into the system when the vehicle traveled over an irregularsurface. For example, when the vehicle traveled over a large bump, theshock absorber and springs would not be able to absorb all of thevertical deflection and hence the vehicle axle would contact the vehiclechassis, a phenomenon commonly known as bottomingout.

To eliminate the aforementioned disadvantages, attempted solutionsincluded the use of condual (concentric-dual) tires or large, lowpressure tires to attain high mobility of the vehicle. Since the airvolume and surface of these tires are both large, the cushioning effectis likewise large, and improved mobility is effected. The deflection oflow pressure, high volume tires rolling over bumpy terrain does nottransmit as much wheel jounce to the suspension components, such asaxles, springs, arms and stops, as would be transmitted by higherpressure, lower volume tires under the same conditions of speed andterrain. Due to the large size of the tires, however, this attemptedsolution is economically disadvantageous. Moreover, large vehicles withlarge wheels will often continue to oscillate in a vertical directionmuch in the manner of a rubber ball. Military vehicles in particular,must traverse extremely rugged terrain. This results in the verticaldisplacement portion of the vehicle suspension system being subjected tothe extreme vibratory motion. As is well known, the suspension system isoften unable to with stand the vertical displacement and hence thevehicle will bottom-out. When traveling over extremely rugged terrain,the force with which the axle meets the stops placed on the bottom ofthe vehicle chassis is extremely large. This results in the stops andsuspension components deteriorating very rapidly.

Accordingly, it is the object of this invention to eliminate theafore-mentioned disadvantages.

nited States Patent C It is another object of this invention to enablethe elimination of the aforementioned stops which are used in aconventional suspension system.

It is another object of the invention to provide a wheeled vehicle ofhigh mobility, having superior sus pension durability.

It is still another object of the present invention to provide a highmobility wheeled vehicle which is safe and reliable, while havingsuperior suspension capability without increasing vehicle cost, weight,and complexity.

It is a further object of the invention to provide a simple andinexpensive means to prevent the vehicle from bottoming-out.

Other objects and advantages of the present invention will becomeapparent to those ordinarily skilled in the art by the followingdescription when considered in relation to the accompanying drawing ofwhich:

FIG. 1 is a plan View of the vehicle incorporating the new and improvedsuspension system according to the invention, with the vehicle shown inphantom.

FIG. 2 is an elevational side view of one of the vehicle wheels in whichthe new and improved suspension system is incorporated.

FIG. 3 is an alternate embodiment of the vehicle suspension deviceaccording to the invention.

FIG. 4 is an elevational view shown partly in section, of the rotarycoupling housing according to the invention.

Briefly in accordance with the invention, it has been discovered that asuspension device has been provided for improving vehicle mobility. Thedevice, according to the invention, incorporates a travel limiting andcushioning means which is mounted to the vehicle and has at least aportion thereof disposed about the vehicle tires. The portion of thedevice which is mounted vertically adjacent the tire interrupts theupward movement of the tire thereby limiting its extreme verticaldisplacement and allowing the tire to act as a cushion stop. This hasthe additional effect of increasing the capacity for wheel displacement,the consequence of which will improve vehicle mobility. The device maybe incorporated in a vehicle which utilizes an automatic pressureregulating systern for pneumatic tires. Although conventionally, theautomatic pressure regulating system is utilized solely to control theair pressure in the respective tires for such purposes as safety andtire stamina, the use of the automatic control apparatus according tothe present invention is utilized primarily for the purpose of improvingthe suspension capability of the vehicle. The combination of the travellimiting means and the apparatus for controlling the air pressure intires permits a greater tire defiection with an accompanying reductionin dynamic loads being introduced into the suspension components and thevehicle proper.

This system also has the advantage of decreased cost, flexibility,space, weight, safety, durability and reliability over the prior artsystems. With respect to the space and cost factor, the standard lowvolume tires that are used conserve vehicle space and cost. In addition,lower maintenance of this suspension system necessitates an addi tionalcost savings. Respecting reliability, an advantage is also obtained inthe capability of being able to operate when the tires have puncturedsince the apparatus for controlling the air pressure in the tires cansupply air for small leaks as the vehicle continues to travel, and onlylarge blow-outs will prevent the vehicle from moving. The flexibility ofthe variable tire air pressure is an advantage in that the driver iscapable of changing tire pressure for sand, snow, 'rnud, ice,cross-country and highway conditions very rapidly when the need arises.Safety aspects of this vehicle include the braking and lowering of thecenter gravity available to the driver by quickly exhausting tire air inan emergency, thereby providing for a faster stop in the event of anemergency. The weight advantage results from the reduction in the massof the suspension components and tires since more energy is absorbed byair volume. The durability of major components is increased bypreventing stresses beyond their yield which is a definite advantage ofthe invention. The elimination of the excessive force of the axleagainst the stops further necessitates a longer life suspension systemin addition to the smoother ride resulting therefrom.

Referring now to the drawings wherein similar numerals will refer tosimilar parts of the various figures, a vehicle is shown in phantom inFIG. 1 having front wheels 12 and rear wheels 14. Mounted on the frontand rear wheels are tires 16 whereas the spare tire is shown at 18. Ascan best be seen in FIG. 2, a pneumatic breather 20 is provided in eachof the vehicle wheels. The breather 20 consists of a tubular assembly,such as the spokes 21, which for tubeless tired wheels, simply connectsholes in the Wheel rim with the rotary air coupling, shown generally at22. For tube-type tires, a special innertube having additional airoutlets is substituted for the standard innertube. The openings to thetires at wheel rim 24 are of sufficient size and spacing to allowrelatively free breathing of the air in the tire as the vehicle passesover bumps and compresses the tire. By means of example only, and notlimitation, four spokes 21 of one inch tubing, equally spaced around therim, are considered sufficient to maintain the desired air pressure.

A rotary coupling housing shown generally at 22, in FIGS. 1 and 2 andmore specific "in FIG. 4, comprises elbow shaped portion 26 and rotatingportion 28. The spokes 21 are secured to rotating portion 28 aboutapertures 27 in any suitable manner such as by welding. A dust seal 30and ring seals 32 are provided in a manner which is well known in theart. Ring seals 32 will allow free rotation without leakage at thepressure involved. Suitable selection of materials and construction ofthe seals will insure durability and environmental compatibility withthe vehicle. A thrust bearing is shown at 34 and is provided to absorblateral forces of the two relatively movable portions of the coupling.The snap ring 36 is provided to secure the thrust bearing 34. As can beseen in FIG. 4, a grease fitting 38 is also provided to adequatelylubricate the relatively movable portions of the coupling.

Attached to rotary coupling 22 by means of union 40, is a flexible hose42. Hose 42 may be constructed of any flexible material such as acovered woven cord with a woven or spiral metal jacket wrapped aroundthe outside to resist mechanical damage. By means of hose 42, air istransmitted to and from the tire through coupling 22 and spokes 21.

As can be seen in FIG. 1, a piping system is shown, comprising pipe ortubing 50, 52, 54, 56, 58, 60 and 62 suitably attached to the vehicle.As shown in the drawing, an air compressor 44 is suitably attached tothe piping system. This compressor may consist of a standard vehicle aircompressor or a conventional belt driven compressor. A reservoir, or airstorage tank and pressure regulator, are desirable, however, notessential. An exhaust or fill valve 46 is provided for permitting air toenter or leave the system by means of tubes and 52. As shown in thedrawing, the compressor 44 is also connected to the valve 46. Valve 46is a solenoid type valve for either lowering tire air pressure byexhausting air from the piping system or raising tire air pressure byadding air to the vehicles air reservoir and/or air compressor 44. Atire pressure and control air gauge 48 is provided to control valve 46.Control switch and air gauge 48 consists of an electrical switch and apressure air gauge mounted on the dash or instrument panel to enable thevehicle operator to direct electrical energy from the vehicle battery tothe exhaust or fill valve 46. Air pressure in tires 16 and 18 is therebycontrolled by suitable actuation of the valve 46. By means of thecontrol switch and air gauge 48, the air pressure in the tires may bedirectly read on a continuating basis and controlled.

Incorporated between the right and left hand portions of the pipingsystem is a solenoid operated cut-01f valve 64. As shown in the drawing,portions 56, 58, and 60 of the piping system are connected to cut-offvalve 64. Operation of valve 64 is controlled by switch 66 which isoperated in response to turning of the vehicle. The primary purpose ofthis valve is for maintaining proper air pres-sure in the vehicle Wheelson either side of the vehicle when the vehicle is negotiating a turn. Ifa sharp turn is negotiated at a high speed, the weight of the vehicle isborne mainly by the wheels on the outside of the curve. Consequently,these outermost tires should have a correspondingly higher air pressurethan under normal circumstances.

Turning now to FIGS. 1 and 2, means for limiting the upward movement ofthe vehicle tires is provided as shown at 68. The travel limiting meansshown in FIG. 2 generally comprises rollers 74 rotatably mounted onspindles 72 which are secured to the vehicle chassis in any suitablemanner. The heavy duty rollers 74 which are mounted above each wheel ofthe vehicle, limits the wheels upward travel and provides additionaltire compression upon deflection of the wheel caused by striking a bumpat high speeds.

The system as previously described enables air from the front tires toescape into the rear and spare tires upon the front tires negotiatingobstructions in the travel surface. Obviously, when the rear tiresnegotiate an obstruction in the travel surface the system causes therear tires to be deflected, air from the rear tires will escape into theremaining portion of the system. By means of the travel limiting device68, which has a portion thereof vertically disposed above the tire asshown in FIG. 2, the vertical displacement of the tire will be limiteddepending on the distance between the travel limit 68 and the respective tires. When the tires contact the travel limiting means 68, thetires will be compressed to a higher degree than exists as a result oftraversing a surface irregularity. This additional tire compression willresult in a greater air volume being directed into the air volumestorage and hence, greater damping of the impact will be eflected.Additionally, the location of the travel limiters above the wheel willprevent the axles of the vehicle from striking the bottom of the chassisand bottoming-out before taking full advantage of the available spacefor Wheel travel.

Referring now to FIG. 3, a second embodiment of the travel limitingmeans is disclosed at 75 comprising a belt 76 mounted on rollers orspindles 78 which are fixedly mounted to the vehicle chassis 70. Theoperation of this embodiment is similar to the above described systemshown in FIG. 2. When the tire is deflected in a vertical direction, itwill contact the travel limiting means 75, thereby limiting its verticalmovements. This of course will increase the compression of the tire andhence will result in a greater air volume being directed into theremaining system. The cushioning effect will again result.

Both of the travel limiting means 68 and 75 are antifriction devices.The main purposes for using this type of system is to eliminate orreduce tangential forces being exerted on the vehicle tire while thevehicle is in movement. If a nonmovable travel limiter were used, thevehicle would be required to travel at slow speeds to insure safeoperation of the vehicle. Other anti-friction devices could likewise beuse such as a transfer ball as is commonly used in table top conveyersor similar ball bearing systems. As shown in the drawing, a brushguard80 may also be provided to protect the flexible hoses and rotarycouplings from damage by scraping on obstructions near the vehicle.

In actual operation of this system, the driver or operator of the highmobility vehicle would pre-set the air pressure in the vehicle tires tothe optimum value as determined by the tire manufacturersrecommendations for the type of terrain or road encountered. Generally ahigh pressure would be used for level, smooth roads and low pressure forrough cross-country terrain.

As the vehicle progresses over bumpy terrain, both the air pressure andthe volume of air will vary. If large ruts, ditches, etc., areencountered, the air volume will decrease while the air pressureincreases. The air pressure in the tires is not restricted in eachindividual tire to increase in value in accordance with ratio of theinitial air volume over the compressed tire volume for a single tire,but it would only rise in proportion to the ratio of the total airvolume in the entire system to the compressed tire volume, a muchsmaller value. For example, if each tire has 5,000 cubic inches of air,and five tires plus piping system have a total of 26,000 cubic inches, a2,000 cubic inch deflection of a tire would yield only 26,000/24,000 ora 108 percent pressure increase instead of 5,000/3,000 or a 167 percentpressure increase. In addition the throttling effect of air flow in theair piping system will reduce or dampen wheel bounce.

When the vehicle traverse a very large or extreme irregularity in thetraverse surface, the wheel will deflect vertically upward until itcontacts the travel limiting device. This will cushion the impact of thebump, dampen oscillations of the suspension system, and also determinethe vertical limit to which the wheel may be vertically displaced. Theanti-frictional nature of the travel limiting device will notsubstantially interfere with the rotational movement of the respectivetires. The additional tire compression caused by the tire engaging thetravel limiting device will result in a greater air volume beingdirected into the total air volume storage system and greater dampeningof the impact will result. This system will thus preclude the axle frombottoming-out. This also precludes and eliminates the deterioration ofthe rubber stops which was prevalent in prior art systems. This systemhas also eliminated cracked vehicle frames which resulted from thesystem bottoming-out against the rubber stops. This system has been ofparticular value in systems in which it is desirable to eliminate wheelwells which normally protrude into the bottom surface of a cargo vessel.Through the use of this system, the distance between the tires and thevehicle body may be less than that of the prior art system, hence thecargo body will have a lower profile which is desirable for loadingpurposes.

Because this system has eliminated the serious nature of the crackedframes and broken rubber stops as a result of the system bottoming-out,transport vehicles can now be manufactured without a stiff suspensionsystem as was previous required. This has a distinct advantage ofproviding a much softer riding suspension system in transport vehicleswhich has not been known in the prior art.

Although the travel limiting means has been shown as being comprised ofmovable rollers or a belt, it should be understood that any system ofanti-frictional elements may be utilized to provide this function andshould not be limited to the two embodiments shown.

While each of the travel limiting systems have been shown with the useof three rollers, it should be understood that any number of rollers canbe suitably utilized to accomplish this purpose.

It should be further understood that the structure for breathing air toand from the tire may be built into the wheel rim at manufacture, ratherthan adding it as a modification to the rim. This structure may besuitably modified according to the particular wheel involved to providegreater space and accessibility for changing tires.

The sealed wheel bearing and combination rotary air valve may beattached to the inside of the wheel, thereby eliminating exterior hosesand brushguards. Piping systems and reservoirs may be built into thevehicle frame structure and air bags may be substituted for conventionalsprings and shock absorbers.

What has been shown, therefore, is a new and improved suspension systemwhich will improve vehicle mobility. This suspension system utilizesexisting air in the tires which accompany the vehicle under stress to astorage volume and its subsequent return as a means for reducing shock.This new and improved suspension system also incorporates a novel travellimiting means to limit the amount of vertical displacement of the tireand further cushion the impact. I wish it to be understood that I do notdesire to be limited to the exact details of construction shown anddescribed, for obvious modifications will occur to a person skilled inthe art.

What I claim is:

1. A suspension device for improving vehicle mobility, for use incombination with a wheeled supported ground vehicle having a sprungpart, comprising,

axle means,

road wheels having pneumatic tires mounted thereon for the resilientsupport thereof, said tires constituting the primary suspensionstructure,

bearing means supporting said wheels on said axle means,

suspension means supporting said sprung part from said axle means, insuperjacent relationship and constituting a second suspension structure,

said suspension means permitting vertical displacement of said roadwheels towards and away from said sprung part,

travel limiting means secured to said sprung part, comprising,

at least one spindle overlying a respective one of said tires,

a freely rotatable roller journaled on each said spindle with thelowermost surface of said roller vertically spaced from the adjacentsurface of said tires a distance less than the spacing of said axlemeans from the under surface of a superjacent sprung part when saidsuspension means is in a first predetermined condition and said secondsuspension structure acts as a principal support for said sprung part,and in contact with said adjacent surface when said suspension means isin a second condition due to intermittent vertical displacement of saidwheel toward said sprung part when said wheel encounters raised groundobstructions, whereby,

in said second condition said roller limits the stress applied to saidaxle and bearing means and said primary suspension structure becomes thesole suspension structure for resiliently supporting said sprung partand axle means and wheels on said ground, transferring ground pressureload through the pneumatic tire to the sprung part.

0 References Cited UNITED STATES PATENTS Re. 24,272 2/1957 Albee 180-74X 676,409 6/ 1901 Berger 180-74 1,394,328 10/1921 Miller. 2,802,5418/1957 Albee. 2,909,244 10/1959 Kraft 188-176 X A. HARRY LEVY, PrimaryExaminer 0 US. Cl. X.R.

